M.S. hug.

"M.S. hug" sounds like something cute, huh?  "Awww, M.S. love you!"  Yeah, what a dumb name.  M.S. hug is a condition from M.S. that feels like "you're being hugged."  No, not even close.  A hug is warm and fuzzy.  M.S. hug feels like you're being constricted by a boa constrictor.  Granted, I have never been constricted by one, but I imagine it would feel pretty close.  I just had my most severe case so far just ten minutes ago.  Gah that feels awful!  It's really hard to breathe.  And holy uncomfortable.  It's almost painful.  It's on the border for me.  It's so uncomfortable it's slightly painful.  It's like being under water and trying to take deep breaths.  But worse.  The "hug" can grip in different places, but it's most common in the upper rib cage, down to the lower abs.  For me, it's tightest in the lung area, but what was weird today, was that I also felt it in my arms.  So weird.  I can't even describe it, it's just weird.  If your arms had lungs, that's what it would feel like.  I don't even know how it's possible, but yeah, in the arms, too.
About.com said this about M.S. hug:

What Causes the "MS Hug?"

It is caused by a lesion on the spinal cord and is technically classified as a neuropathic pain called a “paresthesia,” which refers to any abormal sensation. The sensation itself is the result of tiny muscles between each rib (intercostal muscles) going into spasm. These muscles have the job of holding our ribs together, as well as keeping them flexible and aiding in movement, like forced expiration.

What Does It Feel Like?

Like many MS symptoms, the “MS hug” feels different for different people – it also feels different in the same people on different days or at different times of day. It can be:

• As low as the waist or as high as the chest; rarely it can be felt as high as the shoulders and neck
• Focused in one small area (usually on one side or in the back) or go all the way around the torso
• Worse when fatigued or stressed
• Present in “waves” lasting seconds, minutes or hours or can be steady for longer periods of time
• Described as sharp pain, dull pain, burning pain, tickling, tingling, a crushing or constricting sensation or intense pressure

How Severe Can It Get?

Some people experience difficulty breathing or painful breathing, so severe that it is often perceived as a heart attack or panic attack.  

Such a loving disease!  :)